Ethylene glycol phthalate



atehted Feb. 6, 1934 ETHYLENE GLYooL PHTHA-LATE Charles L. Gabriel and Lloyd Clayton Swallen,v

Terre Haute, Ind.,

assignors to Commercial Solvents Corporation, Terre Haute, Ind., a corporation of Maryland No Drawing.

Application January 24, 1928 Serial'No. 249,198 g 16 Claims (01. 260-103) I Our invention relates to certain new compositions of matter comprising the reaction productsof phthalic acid or phthalic anhydride with ethylene glycol. These substances are .useful as nitro-cellulose plasticizers and as constituents of plastics and synthetic resins; I

Whenethylene glycol is heated with phthalic anhydride, a half ester of phthalic acid forms easily, according to the following equation:

20 It will be noted that this compound contains a free hydroxyl group and a free carboxyl group.

By continuing the heating and conducting it in the presence of an esterification catalyst the 2 remaining free carboxyl and hydroxyl groups may the following formula:

(am-0H, water splitting ed.

It is impossible to conduct the reaction so that the product comprises only the neutral glycol phthalate ester above shown, since one molecule of the product containing the free hydroxyl and the free carboxyl group, which is hereinafter referred to as the half-ester, will react with another molecule, producing various other compounds of high molecular weight.

Thus, two molecules may combine to produce a product that contains no freeesterification groups in accordance with the following equation:

COr-CHFCHiQH water splitting oil;

Alternatively, two

be caused to react, producing a'neutral ester of g low temperatures.

weights of about 900 or temperatures.

molecules of the half-ester 'may combine to produce a contain free carboxyl and hydroxyl groups,

Other reactions tending to produce complex molecular structures will be apparent to those oorcnronron I co-oHl--oHi0io:O'

compound that does thus:

Brenton skilled in the art. For example, if an excess of phthalic anhydride is ester is synthesized,

two free carboxyl groups and being capable of entering into other reactions will be produced by present when the halfa by-product containing the interaction of two moles of phthalic anhydride and one ofethylene glycol, thus:

CHz-O HOzC ori -02o LEE-02C- We have now discovered that it is possible to produce at will compositions of an entirely fluid nature (though viscous) or products so viscous at ordinary temperatures that they cannot be poured. The nature of the products, including the molecularweight,

of synthesis. Liquid weights of 500 or less ducting the reaction depends on the conditions products with molecular may be prepared by conquickly and at relatively Products having molecular above may be produced by the use of longer reaction periods and higher Example I l I 160 grams of phthalic anhydride and 60 grams of ethylene glycol were then cooled. 20 grams heated to 180 C. and

of ethylene glycol and 5 cc. of concentratedsulfuric acid were added and the mixture was then to 115-125 0. for thre heated in an open flask e hours. The product was cooled, washed with sodium hydroxide solution and with water, and was then dried by heating to 180 in an open dish.

The resultant product was apparently liquid in character but was so viscous that it could not be poured except when warm. It was dark brown in color and was difiicultly soluble in benzol. -Its molecular weight was 923 by the freezing point method.

Example II vapor distilledoff, it carried with it, as a concatalystat a temperature of about 100 C stant-boiling mixture, the water formed during the reaction. 7 Heating was continued for three hours, benzol being added from time to time as needed. In this manner, the reaction temperature was maintained at 100 C. or less. The product was washed with alkali and with water, and was dried in vacuo at 150 C. It was a viscous oily liquid showing a molecular weight of 489. It was easily soluble in benzol.

In place of the sulfuric acid used as a catalyst in the specific examples above disclosed, other esterification catalysts such as hydrochloric acid or phosphoric acid may be used. In place of benzol, other inert liquids forming constant-boiling mixtures with water, for example-carbon tetrachloride-rnay be employed.

Now, having described our invention, we claim the following as new and novel:

1. A new composition of matter consisting of the neutral reaction product 01 ethylene glycol and phthalic anhydride.

2. As a new composition of matter, a reaction product of ethylene glycol and phthalic anhydrlde comprising a viscous liquid with a molecular weight in excess of 900.

3. As a new composition of matter, a reaction product of ethylene glycol and phthalic anhydride comprising a viscous liquid with a molecular weight in excess of 900, and difficultly soluble in benzol.

i 4. As a' new composition of matter, a reaction product of ethylene glycol and phthalic anhydride comprising a viscous oily liquid with a molecular.

weight in excess of 400s 5. A process for producing a reaction 'lproduct of ethylene glycol and phthalic anhydride which comprises heating a mixture of said substances in the presence of a mineral acid esterification 6. A process for producing a reaction product of ethylene glycol and phthalic anhydride which comprises heating a mixture of said substances with benzol irrthe presence 0.5 a mineral acid esterification catalyst and removing the water of reaction at a temperature about 100 C. as a constant-boiling mixture with benzol.

'7. A process for producing a reaction product of ethylene glycol and phthalic anhydride which comprises heating amixture of said substances with benzol in the presence of a mineral acid esterification catalyst, removing the water of reaction and benzol at a temperature of about 100 0., washing the. resultant product with alkali and with water, and drying said product at about 150 C.

8.*A neutral ester of ethylene glycol with a phthalic acid. I a

9. Ethylene phthalate.

10. A resin-like material comprising a neutral ester formed by the reaction of ethylene glycol with phthalic anhydride in the presence of sulfuric acid. I .7

11. A resin-like material comprising a neutral ester formed by the reaction of ethylene glycol with phthalic anhydride in the presence of sulfuric acid, at a temperature in excess of 90C.

12. The process of producing a resin-like material which comprises esterifying glycol with an equivalent weight of phthalic anhydride, neutralizing the catalyst of the esterification, distilling away volatile substances, and heating to some temperature above 0.

13. The process of producing a resin-like material which process coinprises esterifying glycol with an equivalent weight of phthalic anhydride, neutralizing the catalyst of the esterification, distilling away volatile substances, and heating to approximately 150 C.

14. The process of producing a resin-like material which process comprises esterifying glycol with an'equivalent weight of phthalic anhydride, neutralizing the catalyst of the esterification, distilling away volatile substances, and heating to approximately 150 C., in vacuo.

15. As a new composition of matter, cyclic ester resulting from the reaction of ethylene glycol and phthalic anhydride. i

16. In a process of producing cyclic esters in the presence of a catalyst the step which com prisescompletely reacting substantially a gram molecular weight of phthalic anhydride with a gram molecular weight of ethylene glycol in the presence of a catalyst. 

